Apparatus for electroplating



Aug. 10, 1943. F. w. THOMAS ET AL 2,326,707 APPARATUS FOR ELECTROPLATING Filed May 29, 1940 2 Sheets-Sheet l ATTORNEYJ.

Aug. 10. 1943.' F .w. THOMAS ET AL 2,326,707

APPARATUS FOR ELECTROPLATING Fil'ed May 29, 1940 2- Sheets-Sheet2 M IIII'IIIIIIIIIWW H INVENTbR:

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Patented Aug. 10, 1943 APPARATUS FOR ELECTIEOPLATING Frederick W. Thomas, Englewood, N. J., and Robert D. -Maclachlan, Barrington, R. 1., as-

signors to Crown Fastener Corporation, Warren,

R. I., a corporation 'of Delaware Application May 29, 1940, Serial No. 337,752 (Cl. 204-199) 4 Claims.

This invention relates to a novel and improved method of electro-plating and to an apparatus which may be used in the practice of that method. The novel features will be best understood a Fig. 2 is a vertical longitudinal section through the apparatus of Fig. 1 as viewed from the top of that figure.

The invention finds particular utility in the plating of links or fastening elements on a tape, such as is commonly used in the manufacture of the type of fastener known as a Zipper. Those links are cast or otherwise secured in spaced relation along one edge of a continuous tape which is later cut into desired lengths for assembling with other lengths and a slider to form the complete fastener.

According to our invention, we provide a tank I of any suitable form, here shown as an elongated tank with rounded ends and in which an electrolyte 2 is placed. Above the tank is disposed a frame 3, the details of which need no description for an understanding of the invention. This frame may be mounted on a column 4 slidable in a support 5 so that it may be raised and lowered as desired. The raising and lowering may be done by any suitable mechanical or pneumatic means, as will be evident to those skilled in the art.

Rotatably mounted in the frame are two sets of shafts 6, on the lower ends of which are rollers l. Preferably, each set of rollers is arranged in a closed figure, here shown as a circle,

so as to form an enclosure, the enclosure being Disposed within each. set of rollers is a plurality of cathodes 9 which may be suspended from negative bus bars ID by metal hooks H. Disposed on the outside of each set of rollers is a plurality. of anodes l2, which may be suspended by metal hooks 13 from a positive bus bar It. We have shown two connections H: for supplying the current to the positive bus bar and similanconnections will conduct the current away metal fastening elements from the negative bus bar 10, Since such connections are not necessary to an understanding of our invention, they have not been shown or described more in detail.

The two sets of rollers are preferably driven, although, if desired, certain of the rollers may be idlers. The motive power may be supplied from a drive shaft l6 which drives the various rollers through the chain drive I! and the other chain and sprocket connections which are plainly shown. As the driving means for the rollers may take anyone of numerous forms, it is not deemed necessary to describe such means in greater detail.

In operation, the entire frame 3 may be raised, for example by a crane which may engage the hook l8, and then a Zipper tape or band IS with It! thereon may be wound around the two sets of rollers. In the illustrated embodiment. this tape is shown as being fed around the set of rollers at the lefthand end of Fig. 2, and wound around that set of rollers spirally towards the bottom. The convolutions of the spiral are kept spaced apart so that the metal links will contact only with the rollers and the electrolyte. When the tape reaches the lower end of one set of rollers, it is passed through a reversing or twisting device 20 and then wound spirally around the other set of rollers and-fed out at the top of the tank and at the right-hand end thereof, as seen in Fig. 2. Suitable guide bars 2| may be located at intervals around thesets of rollers to hold the convolutions 'of the spiraled tape in proper spaced relation, these bars having apertures for the tape and being supported on the frame 3. Thus one side of the links on the tape or band contactswith the rollers in one set and the other side of the same links contacts with the rollers in the other set.

Then the frame may be lowered so as to immerse the rollers or a substantial part thereo. in the electrolyte 2, in which of course both the anodes and cathodes are also immersed, as will be understood in the art.

Then when the plating current is turned on and the rollers are rotated either by some such positive drive as indicated or by'the tape itself, the result will be that current will pass from the anodes l2 through the electrolyte and will deposit plating material upon the articles on the tape and also upon the metallic rollers on the sides facing the anodes at any moment. It of course is understood that both anodes and the plating is to be done.

The area on each roller which contacts with one of the articles to be plated, and that article itself, will have a negative polarity at that time, since it is facing an anode, but as that roller rotates so that it faces towards a cathode, then its polarity is reversed so that it becomes positive and then the metal which has been deposited on the roller will be discharged into the electrolyte rollers maintain a constant diameter so as to provide a constant feeding movement of the tape and may be used for a long period of time without cleaning.

When the deposit of metal on the cathodes has reached a substantial amount, then the cathodes and anodes may be interchanged so that this deposited metal may be used again for plating purposes.

We have shown the two sets of rollers as bein substantially surrounded by anodes and this may be conveniently done by placing two metal bars 22 across the positive bus bar l4 and hanging certain of the anodes from those bars.

In each set of rollers it will be seen. that the rollers are arranged in a continuous line and preferably, but not necessarily, this line forms a closed figure. It is desirable to insulate one side of such line from the other and we have shown the insulation pieces 8 between the rollersfor that purpose. It may also be desirable to establish an insulation by suitable means between the bottom of the tape and the lower ends of the rollers so as to cut down the amount of current which may pass from one side of the line of rollers to the other except through the rollers themselves. Since, however, the specific arrangements of the insulation are not necessary to an understanding of the invention, they have not been illustrated or described except that the insulation pieces 8 are shown in close contact with the rollers..

While we have shown and described the invention as being used for plating links or fastening elements on a Zipper tape, it will be obvious that the invention may be also employed with other articles. For example, it could be applied in the plating of a continuous strip of metal. When applied to the plating of Zipper links, it is found that a fairly uniform plating is achieved in passing the tape around one set of rollers, but the plating is slightly more on one side of the links than on the other and therefore, in order to obtain an absolutely uniform plating on both sides of the links, the tape is preferably reversed between two sets of rollers, as shown.

The rollers may conveniently be made of steel, particularly when the electrolyte is an alkaline solution, which will be used for plating with many 'materials, such for example as brass, tin, cadmium, copper, gold, or silver. When an acid elec trolyte is used, however, the rollers should be of some material such as lead, for example, which will resist the action of the acid. It will be uncathodes will be made of the material with which plated, aside from the method described above, are treated in the usual way, both before and after plating. For example, they may be cleaned with an alkali, then rinsed, treated with an acid, then rinsed, then treated with a cyanide and rinsed again before plating, whereas after plating they may be rinsed and dried. The above steps are more or less standard and may be used with our plating operation as well as when plating by other means.

We have not attempted to define any particular electrolyte, since of course the electrolyte will vary with the material which forms the plating. For example, when plating with brass, the anode and cathode will be brass and the electrolyte may be one of the cyanides of brass. Other electrolytes which will function for plating with other metals are well known in the art and need not be discussed.

The fastening elements or links of Zippers are sometimes made of acetate and given a metallic surface. When that is the case, then these links also may be plated by our method and apparatus, but ordinarily those elements will be made of metal throughout.

While we have shown the invention as practiced by a certain apparatus, the details of that apparatus may be varied considerably withoutdeparting from the scope of the invention as defined in the appended claims.

We claim:

1. Apparatus adapted for the continuous electroplating of electrically conducting articles including separable fasteners, said articles being secured in spaced relation on an electrically nonelectrolytic cell having two chambers containing an anode and a cathode, respectively, said chambersbeing separated by a structure comprising a series of bipolar electrodes mounted for individual rotation about their axes and a series of insulating members alternately disposed in relation to said electrodes and in sliding contact therewith; means to rotate said cylinders whereby a portion of the surface of each cylinder is alternately in the anode chamber and is then negative in relation to the anode therein and in the cathode chamber and is then positive in relation to the cathode therein so that metal deposited on said cylinder in the anode chamber is stripped therefrom in the cathode chamber; and means to continuously pass said articles, mounted on said carrier, successively into contact with each-of said cylinders to deposit metal from said electrolyte on said articles.

2. Apparatus adapted for the continuous electroplating of electrically conducting articles including separable fasteners, said articles being secured in spaced relation on an electrically nonconducting carrier, said apparatus comprising an electrolytic cell having two chambers containing an anode and a cathode, respectively, said chambers being separated by a structure comprising a series of bipolar electrodes mounted for individual rotation about their axes and a series of insulating members alternately disposed in relation to said electrodes and in sliding contact therewith, said cylinders being grouped in such manner that a line drawn spirally thrcugh the axes of the cylindersforms a continuousclosed spiral path; means to rotate eachcylinder about its axis whereby a portion of the surface of each cylinder is alternately in the anode chamber and is then negative in relation to the anode therein derstood that the metal articles which are to be and in the cathode chamber and is then positive in relation to the cathode therein so that metal deposited on said cylinder in the anode chamber is stripped therefrom in the cathode chamber; and means to continuously pass said articles, mounted on said carrier, successively into contact with each of said cylinders substantially through said spiral path to deposit metal from said electrolyte on said articles.

3. Apparatus for the continuous electro-plating of electrically conducting articles including separable fasteners, said articles being secured in spaced relation on an electrically non-conducting carrier, said apparatus comprising an electheir axes and a series of insulating members alternately disposed in relation to said electrodes and in sliding contact therewith whereby at least two groups of cylinders are formed, the cylinders of each group being arranged so that a line drawn spirally through the axes of the cylinders of each group forms a continuous closed spiral path; means to rotate each cylinder of each group about the axis of that cylinder whereby a portion of the surface of each cylinder is alternately in the anode chamber and is then negative in relation to the anode therein and in the cathode chamber and is then positive in relation to the cathode therein so that metal deposited on said surface in the anode chamber is stripped therefrom in the cathode chamber; means to continuously pass the articles, mounted on said carrier, successively into contact with the cylinders of each group substantially through said spiral paths to deposit metal from said electrolyte on said articles; means to convey the carrier from one group of cylinders to another group; and means to turn the carrier through an angle of substantially degrees during the passage of the carrier from one group .of cylinders to another group,

4. Electro-plating apparatus adapted for the continuous electro-plating of a series of electrically conducting articles mounted on a nonconducting carrier comprising an electrolytic cell having an anode and a cathode located, respectively, in an anode chamber and a cathode chamber separated by a rotatably mounted bipolar electrode structure having an axis of rotation and mounted for individual rotation about that 

